Electromagnetic relay



July 21, 1942. M, L, NELSON 2,290,444

ELECTROMAGNETIC RELAY Filed Jan. 27, 1941 INS UL I) T/ON FIG. I

u 1 3 \JNSULAT/ON/TJ 5 5 5 34 L2:33 31/ 327-. YINVENTOR FIGS MARTIN NELSON ATTORNEY Patented July 21, 1942 ELECTROMAGNETIC RELAY Martin L. Nelson, Park Ridge, 111., assignor to Associated Electric Laboratories, Erna, Chicago,

111., a corporation (if-Delaware Application January 2'1, 1941, Serial No. 376,150

6 Claims. till. Milk-87) The present invention relates to relays and more in particular to electro-magnetic switching relays.

The'main object of the present invention is the provision of an improved electro-magnetic relay which is light in weight, rugged and economical in construction, and reliable and positive in operation.

A further object "of the invention is the provision of a relay structure that has a maximum current drain of less than twenty milliamperes and amaximum weight of less than sixty grams.

A still further object of the invention is the provision of a-relay structure having minimum over-all dimensions in order to reduce the amount of space required for the mounting while still maintaining an efllcient magnetic circuit to permit a margin of saiety for operation on extremely low voltages.

A still further object of the invention is they provision of a new and improved contact spring structureincluding a removably mounted armature. 1

One of the important applications of the electro-magnetic relay of the present invention is in Fig. 2 is a view in front elevation of the electro-magnetic relay shown in Fig. i.

Fig. 3 is a right end elevation view of the electro-magnetic relay shown in Fig. 1.

Fig. 4 is a left end elevation view of the elece tro-magnetic relay shown in Fig. 1.

Fig. 5 is an exploded perspective view of one of the pole pieces, the armature, and the restoring spring for the armature.

The electro-magnetic relay shown in the drawing comprises a base member it of insulating material upon which the L-shaped' heel or pole pieces II and 82 of iron or magnetic material are mounted. Supported between the pole pieces H and I2 is the coil It. The armature it is pivoted on one of the pole pieces and is provided with a spring member it for restoring the armature and for maintaining it in pivotal relation with the pole piece as will be described more in detail hereinafter. The circuit controlling contact members it, it and it, which cooperate with the spring 49, are also secured to the base member it in a manner to be described herethe relay equipment of the instrument carried by the balloon which is used in radio-sonde (sounding) by the meteorological service of the Weather Bureau. In order to obtain weather data, a balloon carried instrument is released and as it ascends it, automatically transmits radio signals regarding weather conditions, which signals are received and recorded at the ground-station.

There are three problems which enter into radio-sonde. keep the cost of the balloon carried instrument to a minimum because it is used but once. The second is that the weight of the instrument must be kept to a minimum in order to attain the maximum altitude with the balloon.,, The third is that the balloon carried instrument must be highly efficient because it requires high rates of response so that the time for a complete sounding may be kept within practical limits. It will be seen that the electro-magnetic relay of the present invention is a contributing factor in overcoming the above problems in radio-sonde.

Other objects and advantages of'the present invention will be apparent by reference to the following specification taken in connection with the accompanying drawing, in which:

Fig. 1 is a top plan view of an electro-magnetic relay constructed and arranged in accordance with the present invention.

The first is that it is important tov inafter.

The coil l3 contains a core it! of magnetic material which is reduced in size at each end thereof and inserted into holes provided therefor in the pole pieces H and I2. The core 2G is secured to the pole pieces H and i2 by flaring over the ends 2| and 22 of the core or by ring staking. However, any other method of fastening the core 20 and the pole pieces it and (12 may be used, for example, by tapping the core 25 at each end and inserting screws through the holes in the pole pieces II and i2 into the tapped holes in the core. The coil wiring terminals 23 and .263 which are secured to the coil spool head 25, are insulated from the winding of the coil is by a thin insulating washer 25. Another insulating washer is also placed between the pole piece it and the coil spool head 25.

In order to secure the assembly comprising the coil l3 and the pole pieces It and I2, to the base member ID, lugs 3| and 32 on the pole piece 5 t and lugs 33 and 34 on the pole piece I2 (see Figs. 3 and 4) are provided. The base member I0 is provided with slotted holes therein to receive the lug portions of the pole pieces i and B2. The lugs extend, through and beyond the under surface of the base and are flared out or staked to thereby secure the assembly to the base memher.

The pole piece it is notched to provide lugs 28 and 29 which freely enter notches ii and M, respectively, in the armature it (see Fig. 5) in order to provide a loose pivotal mounting for the armature. This arrangement also prevents relative displacement between the armature and the pole piece II except in a direction perpendicular to the plane of the armature. In order to give "the armature I4 a normal bias away from other with an upwardly extending leg such as 35 which is provided near its extremity with an embossed contact 43 adapted to be engaged by the spring I9. vided with wire connecting portions, such as 31 a (Fig. 3), whereby external wire'connections may be soldered thereto. In order to fasten the terminals I6, I! and I8 to the base member III downwardly extending projections, such as 39 and 40 (Fig. 3) are provided which are inserted through holes provided therefor in the base member I and are bent over, as shown in Fig. 3, to clamp the terminals to the base II).

The spring member I9 on the armature I4, which is tensioned away from the pivotal end of the armature along the portion I (Fig. 1), bears against the embossed contact in the terminal I6. With the tension of the. spring I9 in this direction the free end of the armature is resiliently held away from associated pole piece I2 to maintain the free end of the spring member I9 against the embossed contact in the terminal I7. Accordingly, any external circuit which is soldered to the terminals I6 and I1 is completed through the spring member I9, when the coil I3 of the electro-magnet is in a deenergized condition. When the coil I3 of the electro-magnt relay is in an energized condition, a magnetic circuit is completed through the core 20, the pole pieces I I and I2, and the armature I4, whereupon the armature will pivot on the pole piece II and be attracted to the pole piece I2. By this movement of the armature the spring I 9 will disengage terminal I! and engage the embossed contact on The terminals I6, I! and I8 are also proported by said pole pieces, an armature pivotally the terminal I 8, whereby the circuit which for- '20 dies down, the tension of the spring I5 will move the free end of the armature I4 away from the pole piece I2, thereby opening the circuit which included the terminal I6, spring I9, and

\ terminal'IB and reclose the first-mentioned cir-- cuit through the terminal II.

It will be noted that the sole means for pre- In the event that the armature M has any tendency to stick to the pole piece I2, due to the lag in the flux of the magnetic circuit, a screw or rivet of non-magnetic material may be secured to the armature, in the well known manner, to prevent the armature from actually contacting the pole piece I2.

The tension on spring I9 may be adjusted so that a weaker or a stronger magnetic flux would be required to move the armature by slightly bending the upwardly extending leg, such as 35, of the terminal I6. Furthermore, the stroke of the armature I 4 may be adjusted by slightly bending the upwardly extending leg, such as 35,

of the terminal I'I.

In view of the foregoing it is apparent that an improved electro-magnetic relay is provided in which the coil and the pole pieces for supporting it, and the terminals for external electrical circuits are all mounted upon a base of insulating material. Furthermore, it is also apparent that an improved method of retaining the armature in pivotal engagement by the same spring through which the electrical circuits may be controlled, while still permitting manual removal of the armature and its associated spring without the use of tools.

Having. described the invention, whatis considered to be new and is desired to be protected by Letters Patent will be set forth in the following claims:

-What is claimed is:

1. In a circuit controlling device, a base member, a pair of pole pieces secured to said base member, a core having a winding thereon supmember secured to said armature and having its ends extending beyond the ends of said armature, a first contact member secured to said base engaged by the end of said spring which extends beyond the free end of said armature when said armature engages the said other pole piece, and

' a secondcontact member slidably engaged by the end of said spring which extends beyond the pivoted end 'of said armature whereby an electrical circuit is completed between said contact members through said spring when said armature v engages said other pole piece, said second contact member also providing a slidable contact to perventing the armature II from being displaced from the pivotal portion of pole piece II is the spring I9 which is tensioned along the portion I5 thereof and bears against the terminal I6 at one end and bears against the terminal I! at the other end. With this method of suspending the'armature ll it will be seen that the armature I4 together with its associated spring I9 may be readily removed manually by overcoming sufficient of the tension in the portion I5 of the spring I9 to permit removal of the armature and its spring from the lugs 28 and 29 in the pole piece I I and from engagement with the termi-. nals I6 and I1.

mit the removal of said armature from said device without the use of tools to permanently interrupt the .circuit including said contacts.

2. In a circuit controlling device, a base, an electromagnetic device mounted on said base, an armature for said device removable therefrom without tools, a plurality of terminals secured to said base, and a leaf spring secured to said armature tensioned at one end thereof to engage a first one of said terminals and thereby apply a restoring force to said armature, said spring member at the other end thereof extending beyond the free end of said armature to engage a second oneof said terminals when said armature is in a, restored position and to engage a third one of said terminals when said electromagnetic device attracts said armature, the first one of said terminals and said spring providing a slidable contact therebetween during movement of said armature either responsive to the operation of said device or responsive to the manual revmoval of said armature from said device.

3. In a relay, a base or insulating material, an electromagnetic device mounted on said base including an armature manually removable without the use of tools, a pluralit of terminals secured to said base, and a leaf spring member secured to said armature tensioned at one end thereof to engage one of said terminals, said spring member at the other end thereof extend ing beyond the free end of said armature toengage .a second one of said terminals when the armature is in a restored position and to engage a third one of said terminals when said electromagnetic device overcomes said restoring force applied to said armature, said spring member by its resiliency acting as the sole means preventing the accidental removal of said armature and applying a restoring force to said armature.

4. In a relay mechanism, a flat base, a heel piece and a pole piece secured to said base, a coil mounted therebetween parallel to said base, an armature removably mounted on said heel piece to rotate about an axis vertical to said base to engage said pole piece responsive to energize.-

5. In a circuit controlling device, an electromagnet including an armature removable therefrom without the use of tools, a spring member ,attached to said armature, and contact members,

one end of said spring member normally engaging one of said contact members, said spring movable responsive to the movement of the armature to engage a second of said contact members, the other end of said spring tensioned to normally engage a third of said contact members whereby said armature is maintained in position on said device and whereby manual efiort to overcome the tension of said spring permits the removal of said armature from said device to thereby disconnect any electrical circuit including said spring and said third contact.

6. In a circuit controlling device, an electromagnet including an armature removable therefrom without the use of tools, a spring member tion of said coil, a flat spring secured to said armature between said heel piece and said pole piece and extending beyond the ends of said armature, and a pair of terminals secured to said base, one end of said spring engaging one of said terminals, the other end of said spring slidably engaging the other of said terminals and tensioned to provide the sole force for maintaining said armature in position on said heel piece while permitting manual removal therefrom solely by overcoming the tension of said spring.

attached to said armature, and contact members, one end of said spring member normally engaging one of said contact members, said spring movable responsive to the movement of the armature to engage a second of said contact members, the

other end 0! said spring tensioned to slidably engage a third of said contact members whereby an electrical circuit including the third contact, the said spring and either the said first or the said second contact may be controlled by said electromagnet and whereby said electrical circuit may be disconnected manually without tools by overcoming the tension of said spring and removing the armature from said device.

' MARTIN L. NELSON. 

